Flame-resistant molding compositions containing organic polymers and diorganopolysiloxanes are known in the art. For example, U.S. Pat. No. 3,428,707 to Amos et al describes a flame-resistant composition containing a vinyl chloride polymer in combination with a minor amount of certain elastomeric copolymer modifiers and a small but effective amount of certain diorganopolysiloxanes. Also, U.S. Pat. No. 3,239,579 to Barber et al describes a molding composition containing a minor amount of a non-liquid benzene-soluble diorganopolysiloxane and a major amount of a thermoplastic alkenyl aromatic resin such as polystyrene or a copolymer containing a major proportion of styrene and a minor proportion of alpha-methylstyrene and finely divided silica.
In contrast to the molding compositions described above, the molding compositions of this invention containing organic polymers other than organopolysiloxanes in combination with organopolysiloxanes and optionally silicon dioxide having a surface area of at least 50 m.sup.2 /g exhibit a higher degree of flame-resistance than the previously known compositions.
Therefore, it is an object of this invention to provide a composition which can be molded by compression, injection or an extrusion process to form plastic articles. Another object of this invention is to provide a molding composition having good mechanical properties. Still another object of this invention is to provide a molding composition having excellent electrical properties. A further object of this invention is to provide a molding composition having improved flame-resistant properties.